/*
 * Copyright 2001-2009 Terracotta, Inc.
 *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy
 * of the License at
 *
 *   http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations
 * under the License.
 *
 */

package org.go.trigger.calendar;

import java.util.TimeZone;

import org.go.trigger.Calendar;

/**
 * <p>
 * This implementation of the Calendar excludes a set of days of the month. You
 * may use it to exclude every first day of each month for example. But you may define
 * any day of a month.
 * </p>
 *
 * @see org.quartz.Calendar
 * @see org.go.trigger.calendar.BaseCalendar
 *
 * @author Juergen Donnerstag
 */
public class MonthlyCalendar extends BaseCalendar {

	private static final int MAX_DAYS_IN_MONTH = 31;

	@SuppressWarnings("hiding")
	static final long serialVersionUID = 419164961091807944L;

	// Will be set to true, if all week days are excluded
	private boolean excludeAll = false;

	// An array to store a months days which are to be excluded.
	// java.util.Calendar.get( ) as index.
	private boolean[] excludeDays = new boolean[MAX_DAYS_IN_MONTH];

	public MonthlyCalendar() {
		this(null, null);
	}

	public MonthlyCalendar(Calendar baseCalendar) {
		this(baseCalendar, null);
	}

	public MonthlyCalendar(Calendar baseCalendar, TimeZone timeZone) {
		super(baseCalendar, timeZone);

		// all days are included by default
		excludeAll = areAllDaysExcluded();
	}

	public MonthlyCalendar(TimeZone timeZone) {
		this(null, timeZone);
	}

	/**
	 * <p>
	 * Check if all days are excluded. That is no day is included.
	 * </p>
	 */
	public boolean areAllDaysExcluded() {
		for (int i = 1; i <= MAX_DAYS_IN_MONTH; i++) {
			if (isDayExcluded(i) == false) {
				return false;
			}
		}

		return true;
	}

	@Override
	public Object clone() {
		MonthlyCalendar clone = (MonthlyCalendar) super.clone();
		clone.excludeDays = excludeDays.clone();
		return clone;
	}

	/**
	 * <p>
	 * Get the array which defines the exclude-value of each day of month.
	 * Only the first 31 elements of the array are relevant, with the 0 index
	 * element representing the first day of the month.
	 * </p>
	 */
	public boolean[] getDaysExcluded() {
		return excludeDays;
	}

	/**
	 * <p>
	 * Determine the next time (in milliseconds) that is 'included' by the
	 * Calendar after the given time. Return the original value if timeStamp is
	 * included. Return 0 if all days are excluded.
	 * </p>
	 *
	 * <p>
	 * Note that this Calendar is only has full-day precision.
	 * </p>
	 */
	@Override
	public long getNextIncludedTime(long timeStamp) {
		if (excludeAll == true) {
			return 0;
		}

		// Call base calendar implementation first
		long baseTime = super.getNextIncludedTime(timeStamp);
		if ((baseTime > 0) && (baseTime > timeStamp)) {
			timeStamp = baseTime;
		}

		// Get timestamp for 00:00:00
		java.util.Calendar cl = getStartOfDayJavaCalendar(timeStamp);
		int day = cl.get(java.util.Calendar.DAY_OF_MONTH);

		if (!isDayExcluded(day)) {
			return timeStamp; // return the original value
		}

		while (isDayExcluded(day) == true) {
			cl.add(java.util.Calendar.DATE, 1);
			day = cl.get(java.util.Calendar.DAY_OF_MONTH);
		}

		return cl.getTime().getTime();
	}

	/**
	 * <p>
	 * Return true, if day is defined to be excluded.
	 * </p>
	 *
	 * @param day The day of the month (from 1 to 31) to check.
	 */
	public boolean isDayExcluded(int day) {
		if ((day < 1) || (day > MAX_DAYS_IN_MONTH)) {
			throw new IllegalArgumentException("The day parameter must be in the range of 1 to " + MAX_DAYS_IN_MONTH);
		}

		return excludeDays[day - 1];
	}

	/**
	 * <p>
	 * Determine whether the given time (in milliseconds) is 'included' by the
	 * Calendar.
	 * </p>
	 *
	 * <p>
	 * Note that this Calendar is only has full-day precision.
	 * </p>
	 */
	@Override
	public boolean isTimeIncluded(long timeStamp) {
		if (excludeAll == true) {
			return false;
		}

		// Test the base calendar first. Only if the base calendar not already
		// excludes the time/date, continue evaluating this calendar instance.
		if (super.isTimeIncluded(timeStamp) == false) {
			return false;
		}

		java.util.Calendar cl = createJavaCalendar(timeStamp);
		int day = cl.get(java.util.Calendar.DAY_OF_MONTH);

		return !(isDayExcluded(day));
	}

	/**
	 * <p>
	 * Redefine a certain day of the month to be excluded (true) or included
	 * (false).
	 * </p>
	 *
	 * @param day The day of the month (from 1 to 31) to set.
	 */
	public void setDayExcluded(int day, boolean exclude) {
		if ((day < 1) || (day > MAX_DAYS_IN_MONTH)) {
			throw new IllegalArgumentException("The day parameter must be in the range of 1 to " + MAX_DAYS_IN_MONTH);
		}

		excludeDays[day - 1] = exclude;
		excludeAll = areAllDaysExcluded();
	}

	/**
	 * <p>
	 * Redefine the array of days excluded. The array must non-null and of size
	 * greater or equal to 31. The 0 index element represents the first day of
	 * the month.
	 * </p>
	 */
	public void setDaysExcluded(boolean[] days) {
		if (days == null) {
			throw new IllegalArgumentException("The days parameter cannot be null.");
		}

		if (days.length < MAX_DAYS_IN_MONTH) {
			throw new IllegalArgumentException("The days parameter must have a length of at least " + MAX_DAYS_IN_MONTH + " elements.");
		}

		excludeDays = days;
		excludeAll = areAllDaysExcluded();
	}
}
